The present application is based on Chilean Application No. 1792-03, filed on Sep. 4, 2003, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates generally to the field of controlling all type of rotary DC machines.
The present invention is useful mainly for traction application, railways, trains, cranes, tramcars, elevators, electrical stairs, etc. but by no means is limited to such applications.
2. Discussion of the Background
2.1. Field of the Invention
The field of the invention background is to solve the maintenance problem and pour controllability of the actual dc drives mainly applied in the traction applications.
Now a day more and more dc traction system are been replaced by new AC motor with AC drives too, because these last AC technology is more efficient, more affordable, with very high reliability and controllability performance.
Before our invention was not possible to have one generalized 100% solid state, dc control who can control at the same time the mechanical and electrical variables i.e mechanical as acceleration, speed, breaking power, direction forward reverse and electrical i.e. power, current, voltage, armature and field current, and can regenerate the kinetic energy to the DC supply in breaking operation.
2.2. Discussion of the Background
The application of DC drive is loosing market in the traction industries mainly due to the low efficiency, safety and high labors maintenance that the DC control requirements.
But, migrate from the DC traction system to AC system is very expensive and surely impossible for most of the countries.
For other hands the problems of the DC traction system are mainly in the electrical control used today that use resistances and older contactors with no replaces or spare parts.
If the older DC control of DC traction motors could be replaced by electronic system with equivalent behavior of the AC system the applications of DC motor will be increased because the AC system have one more conversion, then less efficient compared with the DC.
Moreover the AC drives have the problem that must simulate with expensive electronic power circuit a DC series motors to provide high torque at low speed.